I need to write a program in C/C++ that request the user to put in an inode number and then return all of the inode header fields and information back. I am not familiar with linux systems and commands at all. I have found some commands and tried different things that didnt work like I needed.
find -inum inodenumber
will give me the path to the file that contains the specified number. All the information I need comes from istat (according to my research) but I cant get it to work. Im doing
istat FILENAME.jpg
I get the response:
Missing image name and/or address
usage: istat[-B num] [-f fstype] [-i ingtype] [-b dev_sector_size] [-o imgoffset] [-z zone] [-s seconds] [ivV] image inum ...
What do I need to do?
istat only works on disk images, not live filesystems.
There are no system calls in Linux which can look a file up in a live filesystem by its inode number.
Run man istat of course.
In general, you can always get help from the terminal itself by running man.
Try running find with the inode number and then use the filename it generates with stat.
Related
I am running libsvm through weka. Its output accuracy looks good to me, so I am planning to write a svm model by myself. However, weka didn't generate any training parameter, such as number of support vector. Therefore i cannot do anything. Searching the web, i found somebody said it would generate some parameters like the following:
optimization finished, #iter = 27
nu = 0.058475864943863545
obj = -1.871013102744184, rho = -0.19357337828800944
nSV = 9, nBSV = 0 `enter code here`
Total nSV = 9
but how come i didn't see any of them? any step that i missed? please help me. Thanks a lot.
Weka writes the output you mentioned to stderr.
So if you have started weka.sh or weka.bat from a terminal (or "command window" if you are on Windows), you should see that output appear in your terminal window after clicking "classify"
If you want to have access to this information via scripts, you can
redirect the output to a file and read in that file.
Here is how to edit the startup file weka.sh / weka.bat.
Edit this line (it is probably the last line) in order to write log info to a file instead of the terminal window:
java -cp $CP -Xmx8092m weka.gui.GUIChooser 2>>/opt/weka-stable/weka.log &
You can also add a properties file to your home directory to add more fine-grained behaviour.
https://weka.wikispaces.com/Properties+file
(You probably can also access information via the Weka Java API somehow, but you did not ask for that)
I have a quick question, should be relatively simple for those who have some more experience in WMI-command processor than I do (and since I'm an absolute beginner thats not hard :-) )
I fail to understand why wmic /format switch works the way it does. I open up cmd.exe and type
wmic process list brief /format:htable > processlist.html
this does exactly what I want and no bothers further on. Whereas if I go to wmic processor, and try to execute the same command exactly as above...
wmic:root\cli>process list brief /format:htable > processlist.html
I receive the error tag: "Invalid XSL format (or) file name."
Here goes the screenshot. Note I have already copied XSL files from wbem to sys32 dir
Can someone explain to me why these 2 commands that for me look exactly the same, with the only difference that one is executed outside wmic environment and the other one is from inside, the latter one doesn't work? I just fail to understand it.
Please advise so I can comprehend this a bit better! :-)
Try this
copy /y %WINDIR%\system32\wbem\en-US\*.xsl %WINDIR%\system32\
And then
wmic:root\cli>process list brief /format:htable.xsl > processlist.html
Note the presence of the extension after "htable"
You are attempting to use CMD.EXE > redirection while you are within the interactive WMIC context. That can't work.
You can use the WMIC /output:filename switch while in interactive mode. Each subsequent command will overwrite the output of the previous command. You can get multiple commands to go to the same file by using /append:filename instead. You can reset the output back to stdout using /output:stdout.
/output:processlist.html
process list brief /format:htable
/output:stdout
Did you try specifying a full path in the wmic:root\cli>process call? My bets are that the first worked because it output the file to the current directory.
I am using int res = system("uname -p"); in my c++ code.
It will give the the result in standard output by using
fprintf(stdout,"execution returned %d.\n",res);
I want to store this result string in a variable, I am unable to store it.
I google it but unable to find proper solution, Can any one tell me the correct way.
First, you don't need to run the uname command programmatically to get your processor. You can simply run the uname(2) syscall (which the uname command invokes). And you could also read and parse /proc/cpuinfo from your program.
If you wanted to read the output of some command, use popen(3) library function.
See also my answer to a related question.
Actually I have trouble naming the title of this post. Because I don't know how to summarize my meaning in a professional way. But I'll explain my question as below:
I'm running a program written by C++, command is:
./VariationHunter_SC
Then it'll let you type in many parameters:
Please enter the minimum paired-end insert size:
Please enter the maximum paired-end insert size:
Please enter the pre-processing mapping prune probability:
Please enter the name of the input file:
Please enter the minimum support for a cluster:
Obviously I need to type in such parameters one by one to run the program; But I have thousands of such jobs, and need to pre-assign such parameters in script, and submit script to computer.
So how can I do that?
thx
Edit
so how can I make parameter-list?
Just like below?:
140
160
0
mrfast.vh
1
Seems the program cannot recognize these numbers, and distribute numbers..
This depends on how the program actually reads the data that you type in - it's likely that its reading stdin, so you could use separate files with the parameters and pass them in via redirection: ./VariationHunter_SC < parameter-file
It's also possible that the program will accept parameters on the command line, but there's no way of really knowing that (or how) except by whatever documentation the program might come with (or by reading the source code, if it's available and there is no other accurate docs).
Simply use the piping character to pipe the contents of a file to your program
example, in a windows command shell:
echo "asdf" | pause
This will pass "asdf" to the pause program. As a result, pause will print a "Press any key to continue" message, then imediately continue because it will receive the "asdf" string as a response.
So, overall, write or use a program that outputs the contents of your file. Call it, then pipe its output to the program that needs the input.
The unix cat command is such a command that writes the contents of a file to output, or to the input of another executable if you are piping the output.
I need to monitor folders on my linux machine periodically to check whether they are exceeding certain limits.
I have checked stat function call but running stat recursively on all sub folders and files is time consuming and I need to do this for all folders.
Does kernal maintain any datastructures which I can interpret in my program.Or is their any standard api for this.
If you need to enforce limits then use quotas
In case the quota mechanism isn't suitible, then
inotify might be handy:
From wikipedia:
inotify is a Linux kernel subsystem
that acts to extend filesystems to
notice changes to the filesystem, and
report those changes to applications.report those changes to applications.
Type
du -sm directory_name
Will give you the total size of the directory in megabytes recursively.
Type
man du
for help with this command.
You want quotactl:
quotactl -- manipulate filesystem quotas
SYNOPSIS
#include <sys/types.h> /* types needed by quota.h */
#include <sys/quota.h> /* for disk quotas */
Calling stat recursively is the only way to get the current folder size. If you want to continuously monitor the file system, take a look at inotify.
I agree with #Axel. However if you really need to do this in code, you could execute the du shell command via popen:
FILE* pf = popen("du -ch [your folder] | grep total")
Then read the output from the command via the file handle and fgets(...)
Use command du, check this link ...
"How To Check Folder Size"